28 cm/54.5 (11")

Description

In the late 1930s, the Netherlands wanted to build battlecruisers armed with 28 cm (11" ) guns and protection against 20.3 cm (8") shellfire. As the Netherlands Navy had no experience with designing or building warships of this size, they entered into a technical partnership with the German naval authorities in 1939/1940. The gun design for these ships was contracted out to Krupp and was largely based upon the German 28 cm (11") SK C/34 gun used on the small battleships Scharnhorst and Gneisenau. In most respects, the guns and mountings for Design 1047 would have resembled those used on the German ships, although the maximum gun elevation would have been slightly greater.

In reviewing the design concept of these battlecruisers, it should be noted that at the Battle of the River Plate in December of 1939 the similar 28 cm (11") guns of the German Panzerschiffe Admiral Graf Spee out-ranged the 8" (20.3 cm) guns of the British cruiser Exeter. The German guns inflicted severe damage on Exeter at a range that the proposed Netherlands battlecruiser would have been within her immune zone against the British cruiser.

Much of the detail design work needed for the turrets and gunnery arrangements were still being performed by the German designers even after World War II started in September 1939. The work was finally halted after the start of the Western Offensive in 1940.

All German 28 cm guns have an actual bore diameter of 28.3 cm (11.1").

^The gun weight figure above is from "Battleships: Axis and Neutral Battleships in World War II." However, the same source lists the very similar German gun as being considerably heavier at 117,396 lbs. (53,250 kg).

^These guns, like most large caliber German guns, used a "fore charge" which was propellant in a silk bag, and a "main charge" which was propellant in a brass case. The brass case helped to seal the breech of the gun.

Range

Range with 694 lbs. (315 kg) AP

Elevation

Distance

45 degrees

46,590 yards (42,600m)

Armor Penetration

Armor Penetration with 727.5 lbs. (330 kg) AP

Range

Side Armor

Deck Armor

0 yards (0 m)

23.79" (604 mm)

---

8,640 yards (7,900 m)

18.09" (460 mm)

0.76" (19 mm)

16,514 yards (15,100 m)

13.18" (335 mm)

1.63" (41 mm)

20,013 yards (18,288 m)

11.47" (291 mm)

1.87" (48 mm)

30,000 yards (27,432 m)

8.08" (205 mm)

2.99" (76 mm)

The above information is for the projectiles used for the guns on the Scharnhorst class and is from "Battleships: Axis and Neutral Battleships of World War II" for a muzzle velocity of 2,920 fps (890 mps). This is based upon the USN Empirical Formula for Armor Penetration. As the APC projectiles for Design 1047 were somewhat lighter, the armor penetration would likely be somewhat less than the figures in this table, especially for the longer ranges.

Armor Penetration with 727.5 lbs. (330 kg) AP

Range

Side Armor

Deck Armor

10,936 yards (10,000 m)

13.70" (348 mm)

---

16,404 yards (15,000 m)

11.02" (280 mm)

---

21,872 yards (20,000 m)

8.86" (225 mm)

---

27,340 yards (25,000 m)

7.64" (194 mm)

---

The above information is from "German Capital Ships of World War Two" and is for the projectiles used in the guns on Scharnhorst. The data is taken from pre-war Krupp test shoots on their range in Meppen with L/4,4 APC projectiles using RPC/32 propellant against KC-type armor at an impact angle of 70 degrees. It should be noted that RPC/32 propellant was replaced by the more powerful RPC/38 type which was the only propellant used in World War II. As the APC projectiles for Design 1047 were somewhat lighter, the armor penetration would likely be somewhat less than the figures in this table, especially for the longer ranges.

Mount/Turret Data

Designation

Three-gun Turrets: "Design 1047" (3)

Weight

N/A

Elevation

-5 / +45 degrees

Elevation Rate

N/A

Train

about +150 / -150 degrees

Train Rate

N/A

Gun recoil

N/A

Loading Angle

N/A, but probably +2 degrees

Sources

Data from:

"Battleships: Allied Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.